Residential gateways are widely used to connect devices in a home of a customer to the Internet or to any other wide area network (WAN). Residential gateways use for example digital subscriber line (DSL) technology that enables a high data rate transmission over copper lines, or use optical fiber broadband transmission systems, e.g. fiber-to-the-home (FTTH) or fiber-to-the premises (FTTP).
Home networks have become part of everyday life for many customers. A home network consists of a range of heterogeneous devices, which means that the home network is made up of different kinds of devices. All these devices need to communicate with each other. For this interconnection, multiple solutions are available: The home network uses a mixture of solutions, such as wireless and wired network connections. Combining these devices creates a network that allows users to share information and control devices in the home. Examples of networked devices in the home are for example residential gateways, set-top boxes, TVs, personal computers, tablet PCs, smart phones, network-attached storage (NAS) devices, printers and game consoles.
DDS (Data Distribution Service for Real-Time Systems) is a standard governed by the Object Management Group (OMG). It describes a data-centric publish-subscribe middleware that can be used to build distributed real-time systems. Since its formal adoption as an OMG standard in the year 2004 it has become a popular technology used in many different industries such as the airline/aviation industry, the automotive industry, the military . . . . Several commercial and open-source implementations of the DDS standard exist. To allow these different DDS implementations to interoperate, they must implement a second OMG standard, called the Real-Time Publish-Subscribe Wire Protocol-DDS Interoperability Wire Protocol (DDSI) Specification. DDSI specifies how DDS entities (Domains, Participants, Publishers, Subscribers, Readers, Writers, Topics, . . . ) are mapped to DDSI entities (domains, participants, endpoints and optionally topics), the format of the messages that are exchanged between the participants/endpoints, and also valid message sequences of message exchanges between participants/endpoints as well as a mechanism for discovering other participants and endpoints within a DDS domain. The latest version of DDS is currently the version v1.2 and the latest version of the Real-Time Publish-Subscribe Wire Protocol (DDSI) is the version v2.1, which are both published by the OMG on its Internet site under www.OMG.org.
It is the object of the invention, to provide a DDS-based network and DDS-based methods for setting up a multimedia session containing multimedia connections. The DDS-based network is for example a home network including a multitude of devices enabled for DDS, as depicted in FIG. 1a. When leaving a DDS distributed network, classical methods for signalling may be applied, and interoperation entities may be present as needed. Also interoperation of the DDS network with other DDS based islands being connected via a non-DDS network may be applicable, as shown in FIG. 1b. Known signalling systems for setting up media sessions in an Internet Protocol (IP) environment are SIP, H.323, MGCP, Megaco, etc. These systems have the following characteristics:                They are using action based messages.        They are working on functions (protocol entities), that change (session) state based on the requested actions.        The control communication for setting up sessions is between dedicated entities, preconfigured or not.        A signalling control communication for setting up sessions ripples through multiple entities in the network.        
In a DDS environment, which is basically Publish/Subscribe based, the message approach, where a message is sent between dedicated entities is no longer applicable:                DDS uses information exchange, rather than actions, on a Publish/Subscribe basis, on a ‘Topic’ basis. The topic has a name and contains some parameters, which can take any values.        If an entity wants to receive some information, it needs to subscribe to a topic representing the information, on a filtering basis (topics, parameters, values).        Publish means that topic, or parameter, changes are sent around, in principle to any entity that is listening; this can include multiple entities, not only just one.        An entity should only be listening when it has subscribed to a topic, and when an imposed filter allows the listening.        
In software architecture, publish/subscribe is a messaging pattern where senders of messages, called publishers, do not program the messages to be sent directly to specific receivers, called subscribers. Instead, published data is multicasted, without knowledge of what, if any, subscribers there may be. Similarly, subscribers subscribe to particular data, and only receive messages that are of interest, without knowledge of what, if any, publishers there are.
So DDS is data-object (Topic) based instead of message based. The paradigm is different from message based:                In ‘message-based’, action messages are triggering a status change in an entity.        In ‘Data-based’ (e.g. DDS), entities signal the session state, and properties, to other subscribed entities, which will cause such entity to act, and publish also an ‘Updated’ session state, and properties, again to subscribed entities.        